Toxoplasma gondii is an obligate intracellular protozoan
parasite that can invade various organs in the host body, including the
central nervous system. Chronic intracranial T. gondii is known to be associated with
neuroprotection against
neurodegenerative diseases through interaction with host
brain cells in various ways. The present study investigated the
neuroprotective effects of chronic T. gondii
infection in
mice with
cerebral ischemia experimentally produced by
middle cerebral artery occlusion (MCAO)
surgery. The neurobehavioral effects of
cerebral ischemia were assessed by measurement of Garcia score and Rotarod
behavior tests. The volume of
brain ischemia was measured by triphenyltetrazolium
chloride staining. The expression levels of related
genes and
proteins were determined. After
cerebral ischemia, corrected
infarction volume was significantly reduced in T. gondii infected
mice, and their neurobehavioral function was significantly better than that of the uninfection
control group. Chronic T. gondii
infection induced the expression of
hypoxia-inducible factor 1-alpha (HIF-1α) in the
brain before MCAO. T. gondii
infection also increased the expression of
vascular endothelial growth factor after the
cerebral ischemia. It is suggested that chronic intracerebral
infection of T. gondii may be a potential preconditioning strategy to reduce neural deficits associated with
cerebral ischemia and induce
brain ischemic tolerance through the
regulation of HIF-1α expression.